A172188 Partial sums of primes of the form 3*k-1.

2, 7, 18, 35, 58, 87, 128, 175, 228, 287, 358, 441, 530, 631, 738, 851, 982, 1119, 1268, 1435, 1608, 1787, 1978, 2175, 2402, 2635, 2874, 3125, 3382, 3645, 3914, 4195, 4488, 4799, 5116, 5463, 5816, 6175, 6558, 6947, 7348, 7767, 8198, 8641, 9090, 9551, 10018

Offset: 1

Author

Juri-Stepan Gerasimov, Jan 29 2010, Feb 01 2010

Keywords

• nonn

Examples

			a(1)=3*1-1=2, a(2)=2+3*2-1=7.
		

Crossrefs

Cf. A038361.

Programs

Maple

Contribution from R. J. Mathar, Apr 24 2010: (Start)
A003627 := proc(n) if n <= 2 then op(n,[2,5]) ; else for a from procname(n-1)+2 by 2 do if isprime(a) and (a mod 3) =2 then return a ; end if; end do: end if; end proc:
A172188 := proc(n) add( A003627(i),i=1..n) ; end proc: seq(A172188(n),n=1..80) ; (End)

Mathematica

Accumulate[Select[Prime[Range[100]],IntegerQ[(#+1)/3]&]]  (* Harvey P. Dale, Apr 04 2011 *)

Extensions

Entries checked by R. J. Mathar, Apr 24 2010